| 摘要 |
PURPOSE:To improve a high density recording, by reducing a maximum interval of magnetization inversion to facilitate clock regeneration by converting specific code word and code sequence in accordance with values of prescribed bits of three code words based on the 3PM system. CONSTITUTION:In the modulation based on the 3PM system, when the second- the sixth bits of a code word M are all 0 and the first and the second bits of a next code word N are 0, the sixth bit of a code word L preceding the code word M is set to 1 and the code word M is converted to 001001 if the second- the fifth bits of the code word L are all 0. If the second - the fifth bits of the code word L are not all 0, the code word M is converted to 001001; and when the second bit and the fifth bit of the code word M are 1 and 0 respectively and the first - the fourth bits of the code word N are all 0, the sixth bit of the code word M is set to 1 and pattern 001000 is used instead of the code word N. Further, the code word M after conversion is subjected to a prescribed conversion in accordance with values of the code word N and a next code word 0. |
